Electric control system for fuel-oil burners



June 26, 1928. v 1,675,058

. L. L. SCOTT ELECTRIC CONTROL SYSTEM FOR FUEL OIL BURNERS Y OriginalFiled Aug. 12,1922

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ATTORNEY Patented June 26, 1928.

UNITED STATES 1,675,058 PATENT OFFICE.

LEWIS L. SCOTT, OF ST. LOUIS, MISSOURI, ASSIGNOR TO ELECTROL, INC., OFMISSOURI, OF ST. LOUIS, MISSOURI, A CORPORATION OF MISSOURI.

ELECTRIC CONTROL SYSTEM FOR FUEL-OIL IBURNERS.

Application filed August 12, 1922, Serial No. 581,540. Renewed April6,1928.

This invention relates to novel automatic control apparatusparticularly. suited for use with domestic oil burners.

One of the objects of my invention is to provide a simple control switchfor controling the operation of the electric motor and ignition deviceused in oil burning heating system described in my application No. 465,-835, filed April 30, 1921. Another object of my invention is to soarrange the control circuits to the ignition device and motor, that saidmotor switch will not be turned on unless the ignition switch is closed.

The invention is illustrated in the accompanying drawings, in which:

Figure 1 is a front view of my electric control system, showing adiagram of the wiring to the different parts of the system.

Figure 2 is a top view of the control switch shown in Figure 1.

Figure 3 is side view of the top part of the control switch shown-inFigure 1.

Referringnow to the drawings, the nu meral 1 indicates a board ofinsulating material on which are mounted the electromagnets A and -B inopposed relation. Pivotally mounted at .2 is an armature 3 which extendsupwardly above the magnets. The socket 4 is formed at the upper end ofarmature 3, in which socket is mounted a ball 5 supported on a plunger.6 normally pressed upward'by spring 7. Pivotally mounted at one end 8,above the magnet B, is a contact member 9 having on its under side acontact 10, which normally rests upon the upper end of a set screw 11forminga part of contact 12. The contact member 9 could assume thisposition by gravity but for the purpose-of rapidity and security inoperation, I provide a spring 13 for securing such movement of thecontact member from the upperposition. On the upper side of contactmember 9 I provide also a contact I 14 which is adapted to be moved intoengagement with the end of the screw 15 forming a part of a contact 16.Pivotally mounted at 17, above the magnet A, is a contact member 18which is provided onits under side with a contact 19 adapted to restupon the end of screw 20 forming a part of contact 21. The screw 22forms a stop for the member 18 and the screw 23 forms a stop for themember 9. Between the free ends of the two contact members 9 and 18, andprojecting outwardly a short distance from the switchboard 1 is a bar24, the lower edge of which is rounded and located in the path ofmovement of the upper portion of the ball 5. This bar 24 co-operateswith the armature 3 and ball 5 to insure a ,rapid upward movement of therespective the spring 4 instantly forces the said ball,

upward into engagement with the contact member 9 to raise same. The sameoperation occurs when the armature is moved toward the right withrespect to contact member 18. p

' The numeral 25 indicates an electric motor which operates the airblower wheel 26 and the fuel pump 27; the suction pipe 28 runs to a fueltank (not shown) and the discharge pipe 29 runs to the spray nozzle 30.Thefuel spray is mixed with .air from the blower wheel 26 and said fuelis ignited by the spark plug 31. The numeral 32 indicates a transformerfor reducing the main line voltage to 15 volts for use with the sparkcoil'33 which coil furnishes the current for the spark plug 31. As it isonly necessary for the plug 31 to spark for a. short period at the timethe fuel spray starts, 1 provide the thermostatic switch 34 for breakingthe circuit to spark coil 33, the operation of this thermostatic switchwill be described later. 35 is a room thermostat. The battery 36 (ortransformer if desired) is connected to wire 37 which wire runs tomagnets A and B, and to thermostat 35. The main line wires are indicatedby numeral-s 38 and 39; The wire 38 runs through contacts 11 and 12, andthrough the coil 40 on the thermostatic strip 34 and to the motor 25. Itwill be noted that when the armature 3 is in the position shown inFigure 1 the circuit to motor 25 is closed through contacts 10 and 11.The wire 39 runs to the motor 25 and also to transformer 32.. The wire38 runs to transformer 32. The low voltage side of transformer 32 isconnected to spark coil 33 through wire 41 position shown in Figure 1.

and through wire 42; the wire 42 runs through the switch 34 and then tocoil 33 through wire 43. The wire 44 connects to the coil on magnet Band runs to contact 14 through contact 16 to contact 45 of the roomthermostat. The wire 46 connects magnet A to contact 21 and runs throughcontact 19 then through wire 47, through contact 34 and through wire 48to contact 49 of the room thermostat. It will be noted that the circuitto magnet A cannot be closed unless the contact 34 is closed; this is toprevent the turning on of the motor 25 unless the switch 'to spark coil33 is closed.

The operation will now be described. Assuming that the room temperaturedrops below the point at which the thermostat is set, current will besent to magnet A through the wires and contacts before described andmagnet A will move armature 3 to the This operation closes the circuitto motor 25 (whereupon the fuel and air pumps are started) and alsocloses the circuit to transformer 32 which sends current to coil 33 andplug 31, the spark from the plug 31- ignites the fuel spray from thenozzle 30. The coil which is wound around the thermostatic strip 34 andwhich is connected in series with the motor 25 will heat thethermostatic strip 34 and within a minutes time the thermostaticstripwill move upward and break the circuit to the spark coil 33. Thethermostatic strip 34 will remain in this raised position as long as themotor 25 is in operation. hen the room temperature reaches the point'atwhich the room thermostat is set, said thermostat will close the circuitto magnet B through contacts and wires before described and the armature3 will move to the left and break the circuit to motor 25 andtransformer 32 and will also break the circuit to magnet 13. As soon asthe circuit to motor 25 is broken the thermostatic strip 34 will moredownward until it rests on the screw 50. Should the contact 49 bemanually closed before the thermostatic strip 34 reaches the screw 50the magnet A will not be energized until the thermostatic strip 34 restson the screw 50 so that the motor 25 will not start unless the sparkcontrol switch 34 is closed on contact '50.

I claim:

1. In an oil burning heating system, electrically-operated means forprojecting air and sprayed liquid fuel into a zone of ignition,electrical means for igniting the fuel, a high voltage circuit includingthe fuel projecting means, a double magnet switch, the magnets whereofare included in a-low voltage circuit, a second low voltage circuitconnected with said ignition means, means for starting and stopping theflow of electrical current to the ignition means, independent means forbreaking the circuit to the ignition means, an armature adapted to bemoved in opposite directions by energizing the respective magnets ofsaid magnet switch, said switch having a plurality of means, includingsaid starting and stopping means, controlled by the movement of saidarmature in one direction to close the circuit to the fuel projectingmeans, to start the flow of current to the ignition means, and toenergize said independent means for breaking the circuit to the ignitionmeans, and by its movement in the opposite direction, to open thecircuit to said fuel projecting means and to break the low voltagecircuit connected to said ignition means, and a room thermostatconnected to one wire of said first named low voltage circuit and havinga movable member for closing the circuit to one or the other of saidmagnets according to the rise or fall of temperature in the room aboveor below a predetermined degree.

2. In an oil burner control system, means including an electric motorfor projecting fuel into a zone of ignition, means for lighting saidfuel, an automatic switch for controlling the operation of the electricmotor, a piece of thermostatic metal adapted to control the action ofsaid automatic switch, an electric coil for heating said piece of inseries with the electric motor.

In testimony whereof I have hereunto set thermostatic metal, said coilbeing connected

